A woman of around 70 walks very quickly to an empty checkout in a very busy supermarket and sticks just three items - pieces of fruit - on the conveyer belt. That seems a bit odd but you wheel your trolley behind her as clearly there will be little time to wait.
She glares, picks up the fruit and walks away, saying "these people, pushing in, totally oblivious". It is obvious her comments are about you but you haven't pushed in and you can't comprehend why she is bad mouthing you.. You then hear similar comments being made by her behind your back to someone else.
It turns out that she is speaking to her husband who is standing there with an overflowing trolley. You hadn't seen him until that point, They start to wheel the trolley to the adjoining till.